Multiple purpose well tools



July 4, 1957 J. w. KisLlNG nl 3,329,209

. MULTIPLE FURFOSE WELL TOOLS Filed Jan. 4, 1965 6 Sheets-'Sheet l July 4, 1957 J. w. KISLING m MULTIPLE PURPOSE WELL TOOLS Filed Jan. 4, 1965 rfb/77e:

INVENTOR.

July 4, 1967 J. w. KISLING m MULTIPLE PURPOSE WELL TOOLS INVEN TOR.

64 Sheets-Sheet 3 Filed Jan. 1, 1965 July 4, 1967 x. w. KISLING nl MULTIPLE PURPOSE WELL TOOLS Filed Jan. 4, 1965 4 M E, WLM, @M m 6 W m uw I N VENTOR.

July 4, 1967 J. W, K|SL|NG ln 3,329,2@9

MULTIPLE PURPOSE WELL TOOLS Filed Jan. 4, 1965 6 Sheets-Sheet 5 y 73 I@ K /3 E Fly? Hy. 67C a go; I -L/ 4? 72 l w E 47 *Tf/4g f f f L ff 39 90 92 95 July 4, 1967 Filed Jan. 4, 1965 Anf J. w. KISLING m 3,329,209

MULTIPLE PURPOSE WELL TOOLS 6 eats-Sheet 6 United States Patent O 3,329,209 MULTTPLE PURPSE WELL TOLS James W. Kisling III, Houston, Tex., assignor, by mesne assignments, to Schlumberger Technology Corporation, Houston, Tex., aV corporation of Texas Filed Jan. 4, 1965, Ser. No. 423,021 12 Claims. (Cl. 166-128) ABSTRACT OF 'THE DISCLOSURE The disclosure 'describes a. well tool having telescoping inner and outer tubular members that are so arranged with portions of varying cross-sectional `area and fluid seals that an atmospheric chamber and another chamber therebelow `are dened in the annular space between the inner and outer members. Well bore lluids are admitted to this other chamber so that their hydrostatic pressure will be acting upwardly on an outwardly enlarged portion of the inner member to urge it toward the atmospheric chamber. At the same time, the hydrostatic pressure is also acting `downwardly on an inwardly directed shoulder in the outer member -to urge the outer member downwardly. As a result, the inner member is partially supported and the outer member is urged downwardly by known predetermined forces that are related to the hydrostatic pressure of the well bore iluids.

Accordingly, as will subsequently become apparent, this invention relates to well tools; and, more particularly pertains to apparatus for improving the operation of a well tool adapted to conduct a plurality of testing or treating operations where that tool has one member adapted to be `anchored relative to the well bore and another member that is relatively movable thereto.

It is customary to employ a number of diiferent fullbore tools in one string for such well-testing and wellcompletion operations as testing a formation under owing or static conditions, squeeze-cementing, acidizing or fluid-fracturing. To shift the tools into position to conduct these operations, as well as to go from one operation to another, the tubing string is generally used to manipulate a tubular mandrel of each of the various tools into various relative positions. As is typical, such a string of full-bore tools usually includes a full-bore packer for packing-off the well bore to prevent the hydrostatic pressure of the Well-control Huid from being imposed on that portion of the well bore below where the packer is set It is well-recognized that as the number of operations to be performed by a particular tool increase, that tool must be actuated by a correspondingly increasing number of different manipulations to move it from one operating position to another. It will be appreciated, of course, that in general the only basic manipulative movements that may be made are either a longitudinal shifting in either vertical direction or else rotation in one or the other rotative direction.

Those skilled in the art recognize, however, that it is not always feasible -to use all four basic manipulations. For example, many operators object to so-called lefthand rotation since rotation in this direction may inadvertently unthread one or more of the collars coupling the tubing string. Moreover, it is sometimes undesirable to operate a particular tool by multiple rotations in even a right-hand direction and rely upon counting the number of revolutions as an indication of which operating position lthe tool is in since rotation is not necessarily translated faithfully through a tubing `string to a tool that may be several thousands of feet therebelow. Furthermore, in such instances, should a particular well be excessively deviated, it may be necessary to apply an ex- 3,329,209' `Patented July 4, 1967 ICC string. Thus, when the tubing string is pulled to remove the tool, it is more ditlicult to break the connections as the stands of tubing are pulled from the well. Thus, for these reasons, whenever there are more than a few operating positions to be assumed by a tool, it may be necessary to duplicate some of these basic manipulative movements and depend upon variations in degree of -a particular movement to enable an operator to distinguish which operative position his tool is in.

Accordingly, many well tools of'this nature are designed in such a manner that their operating positions are selected by longitudinally shifting the tool mandrel into various longitudinally spaced positions with only a minimum number of operating positions requiring rotative torque.

A typical control arrangement is a so-called ll-slot system in which a lateral pin or pins projecting from one of the members of the well tool is received within a labyrinth arrangement of grooves formed on a mating surface of the other member of the tool. By providing various branch portions in such J-slot systems, it is possible to provide a great number of various and distinct operating positions to be selected by shifting the mandrel of the well tool longitudinally in either direction either with or without an accompanying limited rotative movement. These .l -slot systems have been well accepted, but they are recognized as having some limitations. For example, it is difficult to arrange l -slot systems for each of a group of several well tools for use in a common .string in such a manner that one tool in the string can be moved into another operative position without at the same time shifting another tool into an unwanted position. The problem becomes even more complicated when it is realized that sometimes in a given sequence of operations it is desired that two tools move in conjunction with one another; but at other times in the same sequence, it may be preferred that only one of these tools move without a corresponding movement of the other tool.

A typical example of this is where a packer is set by shifting its mandrel downwardly and released by shifting its mandrel upwardly. Thus, where a tool in the same string is to be moved from one operating position to another by shifting its mandrel upwardly, great care must be exercised in pulling upwardly on the tubing string to prevent such upward travel from also retracting the packer from sealing engagement with the well bore. This particular problem is somewhat minimized on particularly deep wells where the tremendous hydrostatic pressure imposed by the well control fluid will tendto keep the packer set unless a substantial upward pull is exerted on its mandrel. Thus, in such deep wells, by paying careful attention to the weight indicator on the rig door, the operator may pull upwardly on the tubing string without retracting the packer so long as a particular magnitude of upward force is not exceeded. This is not true, however, in more shallow wells where the hydrostatic pressure is not too great and only a slight downward force is imposed by the well control fluid.

It is, therefore, an object of the present invention to provide means for imposing a force in one direction on the mandrel of one well tool that is related to the hydrostatic pressure of the well control fluid so as to permit Aapplication of a force in the opposite direction on the This and other objects of the present invention are obtained by apparatus which includes means responsive to fluid pressure in a well bore for applying a first force of a predetermined magnitude to a movable telescoped member of a first well tool to hold that member relatively fixed as a second force of a lesser magnitude is applied in an opposite direction through the other telcscoped member of the rst well tool to a movable member of a sec-ond well tool coupled thereto.

The novel features of the present invention are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation together with further objects and advantages thereof, may best be understood by way of illustration and example of certain embodiments when taken in conjunction with the accompanying drawings, in which:

FIG. 1 shows a typical string of well tools as they appear within a well bore;

FIGS. lA-lC are schematic illustrations of the tools of FIG. 1 to show their relatively movable elements;

FIG. 2 shows the tools of FIG. 1 in a different operating position;

FIGS. 2A2C are views similar to FIGS. lA-lC but showing the elements in a different relative position;

FIG. 3 shows the tools of FIG. 1 in still another operating position;

FIGS. 3A-3C are views similar to FIGS. lA-lC but showing the elements in still another relative position;

FIG. 4 shows the tools of FIG. 1 in yet an alternate operating position;

FIGS, L11A-4C are viewsI similar to FIGS. lA-lC showing the elements in yet another relative position;

FIG. 5 is a schematic illustration to aid in describing the principles of the present invention; and

FIGS. 6A-6C are consecutive sectional views showing a tool incorporating the principles of the present invention.

Turning now to FIGS. l-4, on the left of each sheet of these drawings is shown a series of full-bore well tools 111-13 tandemly connected to one another and dependently coupled from the lower end of a tubing string 14 within a well bore 15. FIGS. 1-4 depict in sequence the relative positions of the major movable elements of the tools 10-13 as the successive steps of a typical drillstem testing operation are being conducted. To better illustrate the principles of the present invention, the well tools 111-13 have been somewhat simplified to eliminate certain minor structural details; and enlarged portions of the actuated members of the tools are shown schematically on the right of each sheet -of drawings to illustrate the relative positions of these members.

At the lower end of the series of tools depicted in FIG. l, a conventional full-bore packer 1f) is provided for selectively packing-off the well bore 15. A conventional hydraulic hold-down 11 is coupled to the mandrel 16 of the full-bore packer lll for securing the mandrel against upward movement Iwhenever the packer is set and the pressure within the tubing string 14 exceeds the hydrostatic pressure of the control ud in the well bore 15. A typical bypass valve 12, coupled by a tubing sub 17 above the hold-down 11, is suitably arranged to be opened to facilitate shifting of the tools 11i-13 within a fluid filled well bore by diverting a substantial portion of the fluids through the central bore of the retracted packer 10. Connected at the upper end of this string of tools 10-13 is a test tool 13` incorporating the principles of the present invention.

The full-bore packer 10 includes a movable tubular mandrel 16` telescopically disposed within a housing 18 with `an elastomeric packing element 1-9 arranged around its upper end intermediate a fixed abutment 20 and a frusto-conical slip expander 21. A plurality of slips 22 movably mounted around the upper end of the housing 18 are cooperatively engaged with the slip expander 21.

Spring biased drag blocks 23 around the housing 18 secure the housing as the mandrel 16 is shifted downwardly until the slips 22 become anchoringly engaged with the casing 24.

An inwardly projecting lug 25 secured to the packer housing 18 is cooperatively received and confined within a particularly arranged slot 26 formed in the periphery of the mandrel 16. As shown in FIG. 1C, this slot 26 is so arranged that when the lug 25 is in one slot portion 27, the mandrel 16 is secured in an elevated position and cannot shift downwardly with respect to the housing 18. By proper manipulation, however, the mandrel 16 and its slot 26 are movable with respect to the fixed housing lug 25 so that when slot portion 28 is aligned with the lug, the mandrel is then free to move downwardly until slot portion 29 is aligned with the lug.

Accordingly, it will be appreciated that when the slot portion 27 is aligned with the housing lug 25, the mandrel 16 is held in substantially its most elevated position relarelative to the housing 18. With the mandrel 16 in this position, the packing element 19 is, of course, relaxed and `slips 22 are retracted as depicted in FIG. l. To set the packer 16, the mandrel 16 must first be pulled upwardly a slight distance to bring the horizontal slot portion 30 of the slot 26 into alignment with the fixed housing lug 25. Then, upon application of clockwise torque to the mandrel 16, as indicated by the arrow 31 in FIG. 1C, the mandrel will rotate in that direction until lug 25 is shouldered at 28. Once slot portion 28 is aligned with fixed housing lug 25, a downward force on the mandrel 16 will carry the mandrel downwardly to 4set the packing element 19 and slips -22 in the well-known manner, at which time the slot portion 29 will be aligned with the housing lug 25. It will be realized that `the exact position which the slot portion 29 finally assumes in relation to housing lug 25 will vary in accordance with the distance that the mandrel 16 must travel to fully set the packer 10. Thus, an offset slot for securing the mandrel 16 in its downward position can not be accurately located, thereby requiring that a downwardly directed force be maintained on the mandrel to keep the packer 10 set.

The hydraulic hold-down 11 coupled to the upper end of the full-bore packer mandrel 16 is provided with a plurality of piston-like gripping members 32 arranged to be urged outwardly into anchoring engagement with the casing 24 whenever the fluid pressure in the central bore 33 of the hold-down is greater than that outside thereof. Thus, when the full-bore packer 10 is set, the gripping members 32 are driven outwardly into anchoring engagement with the casing 24 to secure the mandrel 16 of the packer in its downward position whenever the pressure below the packer exceeds the pressure within the well bore 15 Iabove the sealingly engaged packing element 19.

The bypass valve 12 has an outer housing 34 in which is slidably mounted a tubular sleeve 35. Spaced O-rings 36 and 37 are suitably arranged around the tubular sleeve 35 so that whenever the sleeve is shifted downwardly within the housing 34, exterior ports 38 in the housing are iiuidly sealed to block fluid communication from the central bore 39' of the housing to the exterior thereof.

An inwardly projecting lug 40 secured to the housing 34 is cooperatively received and confined within a particularly arranged slot 41 formed in the periphery of the tubular sleeve 35. As shown in FIG. 1B, this slot 41 is so arranged that when the lug 4f) is in one slot portion 42, the tubular sleeve 35 is secured in an elevated position and cannot shift downwardly with respect to the outer valve housing 34. By proper manipulation, however, the sleeve member 35 and its slot 41 are movable with respect to the fixed housing lug 40 so that when slot portion 43 is aligned with the lug, the tubular sleeve is then free to shift downwardly until slot portion 44 is brought into alignment with the lug.

Accordingly, it will be appreciated that when the slot portion 42 is aligned with the housing lug 40, the tubular sleeve 35 is held in substantially its most elevated posi tion within the valve housing 34 and the ports 38 are open as depicted in FIG. 1. To close-off the ports 38, the tubular sleeve 35 must first be pulled upwardly a slight distance to bring the horizontal slot portion 45 into alignment with the fixed housing lug 40. Then, upon application of clockwise torque to the tubular sleeve 3S, as indicated by the arrow 416 in FIG. 1B, the sleeve will rotate in -that direction until lug 48 is shouldered at 43. Once slot portion 43 is aligned with the fixed housing lug 40, a downward force on the tubular sleeve 35 will carry the sleeve downward ly to close-off the housing ports 38 at which time the slot portion 44 will be aligned with the housing lug 40.

It will be appreciated from the foregoing descriptions of the operation of the full-bore packer and bypass valve 12 that they function in concert with one another. This coordinated action is, of course, desirable since the bypass valve 12 must be closed whenever the packer 10 is set in or-der to pack-otf the well bore 1S.

Turning now to the test tool 13 and with continued reference to FIG. l, the test tool is suitably arranged to be selectively moved into and secured in three operating positions to provide a corresponding number of operating functions. Thus, the test tool 13 is positionable in:

(l) A normally closed or shut-in position in which tluid communication through the tool is blocked;

(2) A reversing position in which fluid communication is established between the tubing string 14 `and the well bore above the fullbore packer 18; and

(3) An open or testing position to establish fluid communication between the well bore beneath the fullbore packer and the tubing string` The test tool 13 is comprised basically of a tubular mandrel 47 telescopically disposed within a tubular housing 48 with a valve assembly 49l in the lower portion of the mandrel bore that is releasably secured therein by a latching mechanism 58 thereabove. The upper end of the mandrel 47 is connected to the lower end of the tubing string 14 and the lower end of the housing 48 is connected to the tubular sleeve 35 of the bypass valve 12. Thus, whenever the packer 10 has been set and bypass valve 112 closed, the test tool housing -48 is secured to these tools Itl and 12 and the mandrel 47 is moved relative thereto by manipulating the tubing string 14.

The central valve assembly 49 is releasably secured within the mandrel 47 in such a manner that although the test tool 13 is within a well, the valve assembly may be released therefrom `and dispatched to the surface through `the tubing string 14. With the valve asse-mbly 49 removed, a continuous full'opening passage is provided from the surface to that portion 51 of the well bore 15 beneath the full-bore packer 10 for conducting various well-completion operations such as perforating, cementing or fracturing. The valve assembly 49 may also be returned through the tubing string 14 and relatched into position within the mandrel 47. Then, with the valve assembly 49 in place, the test tool 13 is again capable of performing all of its testing functions. Inasmuch Vas the selective releasability of the central valve assembly 49 is incidental to understanding the present invention, in further descrip- -tions of the test tool 13, it will be assumed that the central valve assembly 49 is secured in place within the mandrel 47 and is functioning as a cooperative element thereof.

The mandrel 47 is movably supported within the tubular housing 48 by inwardly projecting, opposed lugs 52 that are cooperatively received and confirmed within a particularly arranged slot system 53 formed in the periphery of the mandrel. As will be subsequently explained, whenever the packer 10 is set, the test tool housing 48 is held stationary and the mandrel 47 is moved relative thereto to operate the test tool 13. Thus, by manipulating the mandrel 47 in a. particular manner, various portions of the slots 53 `are selectively brought into alignment with the lugs 52 to establish the above-mentioned operating positions.

As illustrated in FIG. 1A, the slot system 53 in the 6 mandrel 47 is comprised of a circumferential slot 54 with longitudinal slots 55 (only one being shown) extending downwardly on opposite sides of the mandrel. The lower end of each of the longitudinal slots S5 is terminated by a ltransverse slot 56 which extends a short distance to the left. Part way down each of the longitudinal slots 55, another transverse slot 57 is extended downwardly to the left and terminated by an upwardly directed slot 58.

Thus, it will be appreciated that the mandrel 47 may be placed into any one of three longitudinally spaced positions relative to the housing 48 as: established by the vertical spacing of the slots 54, 57 and 56. Moreover, whenever slot portions 59 in the circumferential mandrel slot S4 are brought into alignment with the fixed housing lugs 52, the mandrel 47 is in its lowermost position relative to the housing 48 and is free to rotate relative thereto for a purpose to be subsequently explained. When fixed housing lugs 52 are confined within slots 58 -as depicted in FIG. 1A, the mandrel 47 is in 4an intermediate longitudinal position relative to the housing 48 and is capable only of being shifted a limited distanceV between slot portions 60 and 61.

Whenever the mandrel 47 has been shifted to its most elevated position, slot portions 62 are in alignment with the fixed housing lugs 52; and lateral por-ts 63 and 64 in the mandrel 47 land upper portion of the central valve 4assembly 49, respectively, are aligned with lateral ports 65 through the housing 48. In either of the two lower longitudinal positions of the mandrel 47, O-rings 66 and 67 around the mandrel above and below the ports 63 fluidly seal the mandrel to the housing 48 to block this fluid communication.

The central valve assembly 49 includes -a central tubular member 68 that extends below the mandrel 47 and is fixed at its upper end by :the l-atching mechanism 50. The lower end of the central tubular member 68 is closed and is provided with radial ports 69 extending from the central bore 70 of the central tubular member. An outer sleeve member 71 slidably ltelescoped raround the lower end of the central tubular member 68 is also closed at its lower end and has lateral ports in its body 72 suitably arranged to line-up with ports 69 whenever the central member is shifted downwardly relative .to the outer sleeve. A compression spring 73 around the central tubular member 58 is arranged between oppositely directed shoulders on the central tubular member and outer sleeve 71 to normally urge the sleeve member into the port-closed position depicted in FIG. 1.

On the lower end of the outer sleeve 71 is a pair of dependently mounted opposed latch members 74 and are biased outwardly by springs 75. As the mandrel 47 is being shifted to its lowermost longitudinal position (position 59), the latches 74 will enter and. become engaged with an inwardly directed annular shoulder 76 around the lower end of the central bore 77 of the tubular housing 48. Notches 78 in the outer edges of the latch members 74 are suitably shaped so that, Whenever properly aligned therewith, the latch members will be pressed outwardly by the springs 75 against the annular shoulder 76 to interlock the notches over the annular shoulder. When the latch members 74 are so engaged with the annular shoulder 76, the sleeve member 71 is secured to the housing 48 and will then remain stationary as the mandrel 47 and tubular member 68 continue to travel downwardly. Continued downward travel of the central tubular member 68 in relation to the now-secured outer sleeve 71 will subsequently bring the ports 69 into alignment with the ports 72 in the sleeve by the time the slot portions 59 have become aligned wih the xed housing lugs 52.

Once the latches 74 have been interlocked within the annular shoulder 76, the outer sleeve member 71 is secured from shifting in either direction until a substantial upward force is applied thereon suflicient to cam the latch members inwardly against the bias of the springs 75 and retract the latches. Thus, so long as the latches 74 are engaged with the annular housing shoulder 76, the mandrel 47 may be pulled upwardly `a short distance (e.g.,

vinto lug position 61) to shift ports 69 in the central tubular member 68 out of alignment with ports 72 without releasing the now-stationary sleeve member 71. Conversely, when the mandrel 47 is returned to its lowermost position (lug position 59) the ports 69 and 72 are again aligned to re-establish liuid communication.

Accordingly, once the latches 74 are secured, the ports 69 and 72 may be opened and closed at will by simply shifting the mandrel 47 downwardly and upwardly between lug positions 59 and 61. The latches 74 are, as previously mentioned, easily released by pulling the mandrel 47 upwardly a sufficient distance to allow the inclined surfaces of the notches 78 to cam the latches inwardly and free them from engagement with the annular shoulder 76.

Turning now to the operation of the string of tools 13. As the tools 10-13 are being lowered into the well bore 15, to perform a typical drillstem testing operation, they are secured in their running-in positions, as depicted in FIG. 1, with the three housing lugs 52, 46 and 25 being confined respectively in slots 60, 42 and 27 as illustrated in FIGS. lA, lB and 1C.

Upon reaching a previously determined depth in the well bore 15, the string of tools 10-13 is halted. Since the drag blocks 23 at the lower end of the string of tools 10- 13 are frictionally engaged with the casing 24, as the tubing string 14 is pulled upwardly, tool mandrel 47, sleeve member 35 and packer mand-rel 16 will sequentially shift into their most elevated positions to bring slot portions 61, 45 and 30 into alignment with housing lugs 52, 40 and 25, respectively. Application of clockwise torque to the tubing string 14 will then sequentially rotate the three members 47, 35 and 16 to bring slot portions 79, 43 and 28 into alignment with housing lugs 52, 40 and 25. Then, by

lslacking off, the full weight of the tubing string 14 is imposed on the string of tools 10-13 to move them into their positions depicted in FIG. 2.

As seen in FIG. 2, the packer 10 has now been set, bypass valve 12 is closed, and the test tool 13 is in its testin-g position. With the packing element 19 now sealingly engaged against the casing 24, the hydrostatic pressure of the well control fluid (typically a mud having certain desirable cha-racteristics) in the annulus 80 above the packing element 19 is no longer imposed -on the remainder 51 o-f the well bore below the packing element.

Accordingly, assuming that the earth formation 81 is capable of producing to some extent, once the hydrostatic mud pressure is removed from the formation, formation pressure will expel whatever natural fluids there may be therein through previously prepared perforations 82 and into the isolated portion 51 of the well bore 15. Since the valve ports 69 and 72 in the test tool 13 are aligned and the tubing string 14 is either at a lower or atmospheric pressure, the natural formation fluids will flow (as represented by the flow arrows) through the string of tools 1li-13 and on upwardly into the tubing string.

The test tool 13 is left in this testing position for a brief interval to allow the well control lluid or mud to be displaced from the isolated portion 51 of the well bore 15 and upwardly into the tubing string 14. Then, whenever the isolated bore portion 51 is believed to be free of mud, the tubing string 14 will be pulled upwardly a short distance while maintaining a slight counterclockwise torque thereon and then slacked-off to close the valve ports 69 and 72. As depicted in FIG. 3, the tool housing lugs 52 have been aligned first with slot portions 61 and now are in slot portion 60 in the mand-rel slot system 53.

Turning now to FIG. 3, only the test tool 13 has changed its position. Once they are closed `and set, the bypass valve 12 and packer 10 remain in the positions previously described and illustrated in FIG. 2. As the test tool 13 was shifted to its closed or shut-in position, slot portions 61 and then 6l) have been brought into alignment with hous- 9 D ing lugs 52 and the central tubular member 68 has shifted relative to the outer sleeve '71 to shut-off ow through ports 69 and 72 of the valve assembly 49. Thus, flow of the natural fluids from the formation 81 will stop.

Accordingly, since t-he residual mud was displaced upwardly into the tubing string 14 when the test tool 13 was first opened, the isolated bore portion 51 now contains only whatever natural fluids that were expelled from the formation 81. When the initial iow of these natural fluids stops, the pressure will begin building up again and will approach the natural formation pressure. Since these fluids are also present in the lower portion of the central bore 77 of the test tool housing 48, the conventional pressure recorders 83 dependently suspended from the `central tubular member 68 will record the pressure of these fluids as it increases to so-called initial shut-in pressure of the formation 81. As is understood by those skilled in the art, obtaining a record of this nature is of value in determining certain characteristics of the earth formation 81.

The test tool 13 is left in the shut-in position illustrated in FIG. 3 for a predetermined time to be certain t-hat the pressure recorders 83 obtain an accurate record of the natural formation pressure while the formation 81 is relatively undisturbed. Then, whenever it is believed that a sufficient shut-in pressure record has been obtained, the tubing string 14 is again picked-up, torqued to the right and slacked-off to re-align slot portions 59 with the tool housing lugs 52 and again shift tubular member 68 downwardly to re-open ports 69 and 72. The packer 10 and bypass valve 12 do not change their positions from those already described and shown in FIG. 2.

Accordingly, with the test tool 13 again in its testing position, as depicted in FIG. 2, uid flow is re-established from the isolated well bore portion 51 into the tubing string 14. The natural formation iiuids will, of course, continue to ow so long as there is a sufficient formation pressure to expel them upwardly into the tubing string 14. As is customary, the test tool 13 will be left in the testmg position for an extended time to enable the pressure recorders 83 to obtain a record of the formation pressure as the formation 81 is being produced. From this record, additional characteristic data can be derived to determine production capabilities of the formation 81.

Once it is believed that sufficient data has been recorded while the well is `iiowing, the test tool 13 is again returned to the shut-in position illustrated in FIG. 3. The test tool 13 is maintained in this position for a short period of time to measure the so-called final shut-in pressure of the formation 81 after it has been produced. This pressure is also recorded on the pressure recorders 83. After this final shut-in pressure is obtained, the drillstem test is complete. It will be realized, of course, that the tool 13 may be repetitively opened and closed to obtain a series of such records.

In accordance with conventional practice, the uids Within the tubing string 14 must now be reversed out of the tubing string. Such reverse circulation is necessary, for example since, should the tubing string 14 be removed from the well bore 15 with formation uids still in it, a potential fire hazard will be created should these fluids be inflammable. Moreover, the drilling crew would fbe hampered by spillage over the derrick door and equipment whenever the stands of tubing are being disconnected.

Accordingly, to move the test tool 13 into its reverse circulating position, the tubing string 14 is picked up and torqued in a clockwise direction to bring slots 56 into alignment with the fixed housing lugs 52. lAs previously explained, this will shift ports 63 and 64 into alignment with ports 65 to allow the uids within the annulus 8@ to be pumped downwardly and into the tubing string 14, It will be appreciated, of course, that as the mandrel 47 is being pulled upwardly, the latch members 74 will be disengaged from annular shoulder 7 6. Once housing lugs 52 are aligned with slots 56, a counterclockwise torque will 9, then bring the slot portions 62 into alignment with housing lugs 52 as seen in FIG. 4.

It will be noted that whenever the test tool 13 is in the reversing position depicted in FIG. 4, that spring 73 will shift the outer sleeve member 71 downwardly to close ports 69 and 72 since the latch members 74 are no longer securing the outer sleeve member. Thus, when it is contemplated that the string of tools 10-13 and tubing string 14 will be removed as soon as the reversing operation is completed, time can be saved by obtaining the final shutin pressure record while the reversing operation is underway. This, of course, makes it unnecessary to return the test tool 13 to its intermediate position (lug position 61) under these circumstances.

Whenever the tubing string 14 is pulled upwardly, to move the test tool 13 into either the shut-in or reversing position, it would seem that there would no longer be any downwardly directed force holding the bypass valve 12 closed and the mandrel 16 in its lower position to keep the full-bore packer 10 sealingly engaged. It will be appreciated, of course, that a shut-in pressure measurement can not be obtained if either the packing element 19 loses its sealing engagement with the casing 24 or the bypass valve 12 opens.

The above-supposed release of either the bypass valve 12 or the mandrel 16 of the full-bore packer 10 will not occur, however, where test tool 13 is employed. To prevent the release of either tool from occurring, it has been found that by cooperatively arranging the mandrel 47 and housing 48 in a particular manner, the hydrostatic pressure of the well control fluid or mud can be utilized to produce a positive, downwardly directed, unbalanced force of a substantial magnitude on the housing. Thus, so long as this resultant downward force is not counteracted by an upwardly directed force of greater magnitude, a downwardly directed force of substantial magnitude will be maintained on the h-ousing 48 and transmitted through the intervening members to both the bypass valve 12 and the packer mandrel 16. Thus, the bypass valve 112 will remain closed and the packer mandrel 16 will stay in its lowered position to maintain the packer element 19 and slips 22 securely engaged with the casing 24 whenever the tester mandrel 47 is being pulled upwardly in a particular manner to be subsequently described.

This positive downward force is obtained by cooperatively arranging the mandrel 47 and housing 48 of the test tool 13 in such a manner that, as depicted schematically in FIG. 5, upper and lower annular chambers 84, 85 are formed within the central portion of the housing. At the lower end of the lower annular chamber 85, an inwardly projecting annular shoulder 86 of the housing 48 is fluidly sealed by O-rings 87 around a reduced-diameter portion 88 of the mandrel 47. At the upper end of this lower annular chamber 85, an enlarged-diameter portion 89 of the mandrel 47 is fluidly sealed by O-rings 90 to the internal bore 77 of the housing 48 to isolate the lower chamber from the upper chamber 84. A port 91 is provided through the housing 48 to admit the well control fluid or mud into the lower chamber 85. The O-rings 67 around the mandrel 47 below the reversing ports 63 fluidly seal the upper end of the upper chamber 84. Since the upper chamber 84 is completely sealed by O-rings 67 and 90, it will be realized that this chamber will remain at substantially atmospheric or reduced pressure.

For purposes of explaining the principles of the present invention, the schematically represented apparatus in FIG. shows only the test tool 13 and the packer 10. It will be appreciated, however, that the same effect will also be obtained with the bypass valve 12 or any other tool having a telescoping joint in the string of tools.

Thus, it will be seen from FIG. 5 that by virtue of the ports 91, the hydrostatic pressure of the well control fluid will act on the lower surface 92 of the enlarged mandrel portion 89 as well as on the upper surface 93 of the inwardly projecting housing shoulder 86. As illustrated by 10 arrows 94 and 95 in FIG. 5, the net result of the resultant forces acting on the apparatus is that the housing 48 will -be held down by -a downwardly directed force 94 and the mandrel 47 will have an upwardly directed force 95 acting on surface 92.

Accordingly, whenever the mandrel 47 is to be shifted downwardly, such as when it is being moved to the testing position, the upwardly directed 4force 95 must be overcome before the mandrel will move. Conversely, whenever the mandrel 47 is to be shifted upwardly, such as when it is being moved to the shut-in position, the force 95 will be acting to move the mandrel upwardly thereby reducing the amount of upward strain that must be taken on the tubing string 14.

It will be realized that the hydrostatic mud pressure should always be greater than the pressure in the well bore portion 51 below the packer 10 since the purpose of the mud is to impose a hydrostatic pressure greater than formation pressure on the formation. Thus, since the pressure below the annular shoulder 86 can not exceed formation pressure during -a testing operation, there should always be a greater pressure above the shoulder than below it. Accordingly, it will be appreciated that irrespective of the magnitude of the pressure differential across annular shoulder 86, so long as the hydrostatic pressure is the greater of the two pressures, there will always be a resulting downwardly acting pressure-induced force 94 applied through housing 48 on the mandrel 16 of the packer 10 each time the tester mandrel 47 is moving relative to the housing 48.

It will be appreciated also that the hydrostatic pressure on the enlarged-diameter portion 89 of the mandrel 47 will impose an upwardly directed force 9S on the mandrel and tubing string 14 as the tubing string is being pulled upwardly. This upward force 95 will, of course, depend solely upon the hydrostatic pressure since the only oppositely directed force acting on the mandrel 47 Will be the weight of the tubing string 14. This, in effect, the upwardly directed pressure force 95 will partially counteract the substantial weight of a conventional tubing string 14 and require less pull thereon to shift the mandrel 47 upwardly.

Since the magnitude of mud pressures are commonly in the order of 10,000 to 15,000 p.s.i.g., the enlarged-diameter mandrel portion 89 need have only a small effective cross-sectional area to develop a very substantial upwardly acting force 95 on the mandrel 47 and tubing string 14 and an equally substantial downwardly acting force 94 on the housing 48. For example, assume that the effective ydifference in annular cross-sectional area of the enlarged portion 89 is only 1 sq. in. and that the hydrostatic mud pressure is 10,000 p.s.i.g. Thus, in this instance, a constant upwardly acting lforce 95 of 10,000 lbs. will be imposed on the tubing string 14 each time the mandrel 47 is shifted. This upward force, of course, reduces by 10,000 lbs. the magnitude of the pull on the tubing string 14 that is required to shift the mandrel 47 upwardly, into relation with the housing lugs 52,

Moreover, the present invention provides a useful guide which aids the operator as he conducts a drill-stem test, Since the upwardly acting pressure force 95 partially counteracts the weight of the tubing string 14, the force required to pull the tubing string is reduced by the magnitude of pressure force 95. Inasmuch as the weight of the tubing string 14 and the hydrostatic mud pressure will be known, -a simple calculation will determine the maximum upward pull needed to move the mandrel 47 upwardly.

Thus, whenever the operator desires to shift the mandrel 47 upwardly, by simply watching the weight indicator on the rig door and maintaining an upward pull only slightly greater than his calculated pull, he will always be assured that the packer 10 has remained seated and is sealingly engaged.

It will be appreciated that unless the unelaborate slot systems 26,41 and 63 are made unduly complicated and complex, the several manipulations previously described could not be performed unless the hydrostatic mud pressure restrains the test tool housing 48. For example, as the tubing string 14 is being pulled upwardly in conjunction with a clockwise torque to shift the test tool 14 into the reverse circulating position, the bypass valve 12 will immediately unjay and willopen unless a downward force is maintained on it. Similarly, should the slot portion 44 be reversed so as to place it to the right, the counterclockwise torque necessary to shift the test tool 13 to the shut-in position would again unjay the bypass valve 12 and allow it to open unless a downward force was maintained.

Turning now to FIGS. 6A-6C, a cross-sectional elevation view is shown of the test tool 13. Since it is obvious to those skilled in the art that such a tool is typically comprised of a plurality of separate tubular elements threaded- Vly connected to one another to facilitate manufacture and assembly, FIGS. 6A-6C have been some what simplified for purposes of greater clarity. Moreover, since the reference numerals used in FIGS. 1-4 are also shown in FIGS. 6A-6C, it is believed necessary to described only the general details of the latching mechanism 50 and one embodiment of the means employed to accomplish the purposes of the present invention.

As previously mentioned, the central valve assembly 49 is releasably secured by latch mechanism 50 within the central bore of the mandrel 47. As has also been described, in all of the testing positions of test tool 13, the valve assembly 49 remains in place within the mandrel 47 and need not be removed except to provide a continuous full-opening passage from the surface of the ground to that portion 51 of the well bore 15 beneath the fullbore packer 10.

The central tubular member 63 of the valve assembly 49 extends upwardly into the central bore of the mandrel 47 and is normally secured in place there by the latching mechanism 50. O-rings 96 below the lateral ports 64 uidly seal the central tubular member 68 with respect to the mandrel 47. A bearing 97 is disposed around the central tubular member 68 and rests on the upper face of shoulder 98 on the central tubular member. A plurality of threads 99 `are formed around the uppermost end portion of the central tubular member 68 for a purpose to be described subsequently.

A tubular sleeve member 100 is rotatively disposed around the upper end portion of the central tubular member 68 with the lowermost end of this sleeve member resting on lthe upper face of the bearing 97. The tubular sleeve member 100 is free to rotate relative to the central tubular member 68, but is prevented from moving in o either longitudinal direction by an inwardly directed annular shoulder 101 around its lower end that is disposed underneath an outwardly directed shoulder 102 around the central tubular member.

Longitudinal slots 103 are provided on opposite sides of the upper end of the tubular sleeve member 100 for receiving pivotally mounted latch iingers 104 therein. Springs 105 normally bias the latch fingers 104 radially outwardly to urge the upper ends of each of the fingers into complementary recesses 106 formed on opposite sides of the central bore of the mandrel 47 where the upper ends of the iingers are engaged under downwardly directed shoulders 107 in the mandrel.

Longitudinally extending splines 108 are provided within the internal bore of the tubular sleeve member 100, with these splines being slidably received in substantially longer spline grooves 109 formed in the periphery of a tubular jack-screw member 110. Internal threads 111 at the lower end of the jack-screw member 1.10 are threadedly engaged with the threads 99 at the upper end of the central tubular lrnember 68. A release sleeve 112 is slidably mounted in the upper most end portion of the jackscrew 110 and has its upper end enlarged in diameter in such a manner as to provide an upwardly diverging tapered surface 113. A spring 115 normally biases the release sleeve 112 upwardly to normally maintain the tapered surface 113 a slight distance above inwardly projecting lugs 114 on the latch iingers 102.

Accordingly, as best seen in FIGS. 6A-6C, when it is desired to release the central valve assembly 49 from its normal position, in one manner of operation the test tool mandrel 47 is appropriately manipulated so as to bring the circumferential slot portion 54 into alignment with the housing lugs 52. It will be realized that with the circumferential slot 54 being in alignment with the housing lugs 52, the mandrel 47 is free to rotate with respect to the housing 48. In this position ofthe mandrel 47 relative to the housing, a thrust bearing 116 disposed around the mandrel is brought into engagement with the upper end of the housing to carry the downward thrust as the tubing string 14 is rotated. As the mandrel 47 is rotated, the torque is transmitted through the latch ingers 104 to rotate the tubular sleeve member 100 as well. Inasmuch as the tubular sleeve member is held against longitudinal travel by the inner engagement of shoulders 101 and 102, as the sleeve member rotates splines 108 will also rotate the jack-screw member 110.

It will also be recalled from the previous description of the operation of test tool 13 that whenever the circumferential slot portion 54 is in alignment with housing lugs 52, the latches 74 on the lower end of the central valve assembly 49 are co-engaged with the inwardly projecting shoulders '76 in such a manner that the central tubular member 68 is secured against rotation with respect to either the housing 48 or the mandrel 47. Thus, as the jack-screw member is rotated, the threads 111 at the lower end of this member will be threaded downwardly on the threads 99 at the upper end of the central tubular member 68. Downward travel of the jack-screw member 110 will carry the release sleeve 112 downwardly to bring the tapered portion 113 at its upper end downwardly and into engagement with the inwardly projecting lu-gs 114 on the latch lingers 104. As best seen in FIG. 6A, it will be appreciated that as these tapered surfaces 112 move downwardly and into engagement with the lugs 114, the latch fingers 104 will be cammed radially inwardly so as to release their upper ends from the recesses 107. Accordingly, once the jack-screw member 110 is threadedly rotated to its lowermost position (with respect to the threads 99 on the upper end of the central tubular member 68), the latch fingers 104 will be removed from engagement with the recesses 106 and the entire central valve assembly 49 (which includes the central tubular member 68) will be unlatched with respect to the mandrel 47.

Accordingly, by providing swab cups (not shown) at the upper end of the sleeve member 100, when the test tool 13 is in the reverse-circulating position and once the central valve assembly 49 is freed it may be pumped upwardly in the tubing string 14 and recovered at the surface of the ground. Moreover, a retrieving tool (not shown) can be lowered on a wireline and secure a fishing neck (not shown) at the upper end of the tubular sleeve member 100 to pull the freed valve assembly 49 upwardly through the tubing string 14. Still another manner of release -may be employed by lowering another type oi retrieving tool (not shown) provided with a downwardly extending central or probe-like member (not shown) that is suitably arranged to engage the uppermost end of the release sleeve 112 and depress it downwardly with respect to the sleeve member 100 and allow the lingers 104 to be cammed inwardly by the outer surfaces of the recesses 106. Inasmuch as these features of the test tool 13 play no part in the principles of the present invention, it is believed that the above description is sufiicient and no further description of the details of the release of the central valve assembly 49 is needed to fully understand the present invention.

Turning now to FIG. 6B, one manner of providing the separate chambers 84 and 85 is shown. The enlargeddiameter portion 89 previously described With respect to FIG. may be provided by a slidable annular member 89 which is fluidly sealed with respect to the housing 48 by O-rings 90 and with respect to the mandrel 47 by O-rings 117. A spring 118 between the annular member 89 and a shoulder 119 on the mandrel 47 normally urges the annular -member upwardly against another shoulder 120 on the mandrel. Thus, it will be appreciated that the annular member 89' will function in the same manner as the schematic representation of FIG. 5 already described in detail.

A venting port 121 through the mandrel 47 will prevent drilling fluid from becoming entrapped within the upper chamber 84 should such fluid leak into the chamber. It will be realized that should a suiiicient quantity of fluid leak into the upper chamber 84, the mandrel 47 could not be shifted upwardly without relieving whatever uid was in the chamber. Thus, should such a leak occur, as the mandrel 47 is pulled upwardly the entrapped fluids will shift the annular member 89 downwardly in relation to the mandrel until port 121 is uncovered so as to bleed off the entrapped fluid. Moreover, when the test tool 13 is removed from a well bore, should there be any drilling fluid at a high pressure in the upper chamber 84, when this pressure exceeds that in the lower chamber 85 the annular member 89 will be urged downwardly to uncover port 121 and bleed off the pressure. It will be appreciated, of course, that the annular member 89 otherwise will remain in the position shown in FIG. 6B and port 121 will remain closed off by the spacedapart C-rings 117.

Accordingly, it will be appreciated that the present invention has provided new and improved means whereby one movable element in a string of well tools may be moved without another movable element in the same string of tools also moving and Without employing a complex mechanism or complicated arrangement of lugs and slots which has heretofore been required. It will be understood, of course, that while the principles of the present invention have been described in conjunction with one particular configuration of slot systems and tools, this same principle may be adapted for use in any plural group of well tools where it is necessary to move many elements in several relative motions.

While particular embodiments of the present invention have been shown and described, it is apparent that changes and modications may be made without departing from this invention in its broader aspects and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

What is claimed is:

1. In a well tool adapted for use in a well bore having fluid therein: rst and second telescoping members arranged for movement between an expanded position and a contracted position in relation to one another, one of said telescoping members being adapted for connection to a string of pipe; means for securing the other of said telescoping members in relation to a well bore; and means responsive only to hydrostatic pressure of well bore uid for retarding the movement of said one telescoping member toward one of said positions and expediting the movement of said one telescoping member toward the other of said positions.

2. In a well tool adapted for use in a well bore having iluid therein: iirst and second telescoping members arranged for movement between an expanded position and acontracted position in relation to one another, one of said telescoping members being adapted for connection to a string of pipe; means responsive to movement of said one member toward one of said positions for securing the other of said telescoping members in relation to a well bore; and means responsive only to hydrostatic pressure of Well bore fluid for retarding the movement of said one telescoping member toward said one position and eX- pediting the movement of said one telescoping member toward the other of said positions.

3. In a well tool adapted for use in a well bore having uid therein: rst and second telescoping members arranged for movement between an expanded position and a contracted position in relation to one another, one 0f said telescoping members being adapted for connection to a string of pipe; means responsive to movement of said one member toward one of said positions for securing the other of said telescoping members in relation to a well bore; and means responsive only to hydrostatic pressure of Well bore fluid for retarding the movement of said one telescoping member toward said one position and expediting the movement of said one telescoping member toward the other of said positions while maintaining said other telescoping member in said secured relationship.

4. In a well tool adapted for use in a well bore having fluid therein: rst and second telescoping members arranged for movement between an expanded position and a contracted position in relation to one another, one of said telescoping members being adapted for connection to a string of pipe; means responsive to movement of said one member toward one of said positions for securing the other of said telescoping members in relation to a well bore; and hydraulic means responsive only to hydrostatic pressure of well bore Huid for applying a rst force in one direction to said one member to retard its movement toward said one position and to expedite its movement toward the other of said positions and for simultaneously applying a second force in the opposite direction to said other member to maintain said other member in said secured relationship.

5. In a well tool adapted for use in a well bore having fluid therein: first and second members telescoped together and defining therebetween first and second longitudinally-spaced annular chambers of different cross-sectional annular areas, said telescoping members being arranged for movement between an expanded position and a contracted position in relation to one another, one of said telescoping members being adapted for connection to a string of pipe; means responsive to movement of said one member toward one of said positions for securing the other of said telescoping members in relation to a Well bore; and hydraulic means responsive to hydrostatic pressure ofv well bore fluid for applying a iirst force to said one member to retard its movement toward said one position and to expedite its movement toward the other of said positions and for simultaneously applying a second force to said other member to maintain said other member in said secured relationship, said hydraulic means including first, second and third longitudinally-spaced sealing means for respectively fluidly sealing said telescoping members relative to one another above said first chamber, intermediate said chambers and below said second chamber and passage means providing communication for well bore fluid into said chamber having the larger crosssectional area, the other of said chambers being sealed.

6. In a well tool adapted for use in a well bore having iiuid therein: a tubular housing member; a movable body member having an enlarged portion and a reduced portion telescopically received in said housing member, said body member being adapted for connection to a string of pipe and movable in relation to said housing member between an expanded position and a contracted position; means responsive to movement of said body member toward one of said positions for securing said housing member in relation to well bore; and hydraulic means responsive to hydrostatic pressure of well bore fluid for applying a rst force to said body member to retard its movement toward said one position and to expedite its movement toward the other of said positions and for simultaneously applying a second force to said housing member to maintain said housing member in said secure-d relationship, said hydraulic means including fist and second longitudinally-spaced sealing means for fiuidly sealing said enlarged portion of said body member relative to said housing member to i provide a sealed first chamber, third sealing means for fluidly sealing said reduced portion of said body member relative to said housing member at a point spaced from said other sealing means to provide a second chamber, and passage means providing fluid communication for well bore uid into said second chamber.

7. In a well tool adapted for use in a well bore having uid therein: a first member; second and third members respectively telescopically arranged at opposite ends of said first member, each of said second and third members being movable in relation to said rst member between an expanded position and a contracted position, said second member being adapted for connection to a string of pipe; means responsive to movement of said first member relative to said third member toward one of their said relative positions for securing said third member in relation to a well bore and responsive to movement of said rst member relative to said third member toward the other of their said relative positions for freeing said third member in relation to a well bore; and hydraulic means responsive to hydrostatic pressure of well bore fluid for `retarding the movement of said second member relative to said first member toward one of their relative positions and expeditng the movement of said second member relative to said first member toward the other of their relative positions.

8. In a well tool adapted for use in a well bore having fluid therein: a first tubular member; second and third members respectively telescopically arranged at opposite ends of said rst member, each of said second and third members being movable in relation to said first member between an expanded position and a contracted position, said second member having an enlarged portion and a reduced portion received in said rst member and being adapted for connection to a string of pipe; means responsive to movement of said first member relative to said third member toward one of their said relative positions for securing said third member in relation to well bore and responsive to movement of said first member relative to said third member toward the other of their said relative positions for freeing said third member in relation to a well bore; and hydraulic means responsive to the hydrostatic pressure of well bore fluid for retarding the movement of said second member relative to said first member toward one of their relative positions and expediting the movement of said second member relative to said first member toward the other of their relative positions, said hydraulic means including first and second longitudinally-spaced sealing means for iiuidly sealing said enlarged portion of said second member relative to said first member to provide a sealed first chamber, third sealing means for fluidly sealing said reduced portion of said second member relative to said first member at a point spaced from said other sealing means to provide a second chamber, and passage means providing fluid communication for well bore huid into said second chamber.

9. In a well tool adapted for use in a well bore having fluid therein: a tubular housing member; a body member telescopically received in said housing member and movable with respect to said housing member between an expanded position and a contracted position; means responsive to movement of said body member toward said contracted position for securing said housing member relative to a well bore; means adapted for selectively controlling fluid communication between a well bore and a pipe string disposed in a well bore including first a-nd second telescoping tubular members arranged for movement relative to one another between an expanded position and a contracted position, said first member being adapted for connection to a pipe string and said second member being connected to said body member, and valve means selectively operable lresponsive to movement of said first member relative to said second member; and hydraulic means responsive to hydrostatic pressure of l5 well bore fluid for applying a first force on said second member to maintain said body member in a contracted position relative to said housing member and for simultaneously applying a second force on said first member to expedite movement of said first member toward an expanded position in relation to said second member.

10. In a well tool adapted for use in a well bore having uid therein: means for packing-off a well bore including a tubular housing member and a body member telescopically received in said housing member and movable with respect to said housing member between an expanded position and a contracted position and expansible packing means operatively disposed between said housing member and said body member and expandable in response to movement of said body member toward said contracted position for packing-olf a well bore; means adapted for selectively controlli-ng iiuid communication between a well bore and a pipe string disposed in a well bore including first and second telescoping tubular members arranged for movement relative to one another between an expanded position and a contracted position, said first member having an enlarged portion and a reduced portion received in said second member and being adapted for connection to a pipe string and said second member being connected to said body member of said packing-off means, and valve means selectively operable in .response to movement of said first member relative to said second member; and hydraulic means responsive to hydrostatic pressure of well bore fluid for applying a rst force on said second member to maintain said body member in a contracted position relative to said housing member and for simultaneously applying a second force on said rst member to expedite movement of said first member toward an expanded position in relation to said second member, said hydraulic means including rst and second longitudinally-spaced sealing means for fluidly sealing said enlarged portion of said rst member relative to said second member to provide a sealed rst chamber, third sealing means for uidly sealing said reduced portion of said first member `relative to said second member at a point spaced from said other sealing means to provide a second chamber and passage means providing fluid cornmunication for well bore fluid into said second chamber.

11. As a subcombination, a well tool adapted for use in a well `bore having Huid therein: a tubular housing member having a bore with at ileast a portion thereof being of a uniform diameter; a tubular body member having an enlarged outer-diameter upper portion, an enlarged outer-diameter intermediate portion and a reduced outer-diameter lower portion telescopically received in said housing bore and movable with respect to said housing member between an expanded position and a contracted position, said body member `being adapted at its upper end for connection to a pipe string; valve means carried by said body `member and responsive to movement of said body member relative to said housing member for selectively controlling uid communication between a well -bore and a pipe string; and hydraulic means responsive to hydrostatic pressure of well bore fluid for regulating the travel of said body member in at least one direction between said positions including first and second sealing means respectively fluidly sealing said upper and lower portions with respect to said housing member, third sealing means carried on said intermediate body portion and uidly sealing said body member thereat to said uniform bore portion of said housing member for providing a sealed iirst chamber above said third sealing means and a second chamber therebelow, and passage means providing fluid communication for well bore uid into said second chamber.

12. As a subcombination, a well tool adapted for use in a well bore having uid therein: a tubular housing member having a bore wit-h at least a portion thereof being of a uniform diameter; a tubular body member having. an enlarged outer-diameter upper portion and a reduced outer-diameter lower portion telescopically received in said housing bore and movable with respect to` s-aid housing member between an expanded position and Aa contracted position, said body member being adapted at its upper end for connecti-on to a pipe string and having stop means on said reduced-diameter porti-on; valve means carried by said body member and responsive to movement of said body member relative to said housing member for selectively controlling fluid `communication between a 4well bore and a pipe string; hydraulic means `responsive to hydrostatic pressure of welll bore Huid for regulating the travel of said body member between said positions including ain annular member slidably mounted around said reduced-diameter body portion below said stop means, spring means normally ybiasing said annular member upwardly against said stop means, rst and second spacedapart sealing means fluidly sealing said annular member to said reduced-diameter body portion, third sealing means liuidly sealing said annular member to said uniform `bore portion of said housing member,` fourth sealing means fluidly sealing said upper body portion to said housing member for providing a sealed upper cham- 18 ber above said annular member, fifth sealing means fluidly sealing said lower body -portion to said housing member for providing a lower chamber below said annular member, and rst passage means providing uid communication for well bore uid into said tl-ower chamber; and second passage means providing fluid communication from the `bore of sai-d body member to the exterior thereof at a point intermediate of said rst and second sealing means whenever said annular member is in its said normal position.

References Cited UNITED STATES PATENTS 2,690,807 10/1954 Moos'man 166-150 3,065,796 11/1962 Nutter 166-226 3,190,360 6/1965 Farley 166-226 3,249,124 5/1966 Berryman 166-226 X 3,259,192 7/1966 Hyde 166-150 CHARLES E. OCONNELL, Prima/'y Examiner. D. H. BROWN, Assistant Examiner. 

1. IN A WELL TOOL ADAPTED FOR USE IN A WELL BORE HAVING FLUID THEREIN; FIRST AND SECOND TELESCOPING MEMBERS ARRANGED FOR MOVEMENT BETWEEN AN EXPANDED POSITION AND A CONTRACTED POSITION IN RELATION TO ONE ANOTHER, ONE OF SAID TELESCOPING MEMBERS BEING ADAPTED FOR CONNECTION TO A STRING OF PIPE; MEANS FOR SECURING THE OTHER OF SAID TELESCOPING MEMBERS IN RELATION TO A WELL BORE; AND MEANS RESPONSIVE ONLY TO HYDROSTATIC PRESSURE OF WELL BORE FLUID FOR RETARDING THE MOVEMENT OF SAID ONE TELESCOPING MEMBER TOWARD ONE OF SAID POSITIONS AND EXPEDITING THE MOVE- 